Toolholder



H. R. PLUMMER A ril 20, 1954 TOOLHOLDER 2 Sheets-Sheet 1 Filed NOV. 29,1951 W W E Ma i o April 20} 1954 H. R. PLUMMER 2,675,604

TOOLHOLDER Filed Nov. 29, 1951 2 Sheets-Sheet 2 Patented Apr. 20, 1954 wTOQLHOLDEB pplication N Yem erZ- 951, Serial No, 25833 This e in r lat st ,eut ie 3299 5 more particularly to tocl hglgiers fiqr, ,sirppprtingtool bits madelof tungsten. carbicieqr ether cut ting materials.

It is an object of the invention to prcvi de a tool holder havinimproved means e hat n up a :tool bit.

A further object is t rovide a i92 ho e having tool backing means soccnstnuct ed asito provide. fcr accurate 'lqngit dinal adiqs tn ent 9fthe tool bit.

A further object ,is to. q i e i99 .ll l fi having toql backing mea s.Which is easily djustable and which neverth less reliah 3 1%? tains itsadjustment during use.

A further b c i R rpm-title t 99 1h91dQ having tool backing means thefqr n cffa wedge member to ethenwithqlem l 1 195 35 for adjustablypositioning the wedge m leer.

A further object is to pro id bit- 33mm having a w r hap d back n membew eh is adjustable an ularlvaswel a lqn i u x f so that fullbearingcontact car hen a: ecl between the backing men beiyand the 1) cl it,even vthough t t o bit and "the hack n mepfberare nut-exactly Square.

-A .still: further abject-im mio iqem mla ad tool .holder which is nnusi ally manufacture.

Further objects and aglvant a gespf the invention wniapnea i pm th Qlwin adiaj scription taken with the accpmpanying hawings in which:

Figure 1 is a P a e wto w w owe llustrative tool constructed inacccrgiance with the vention.

-Fig..2vis an elevationahview cf the -tpol taken longitudinally thereof.

Fig. 3 is a transverse sectional view-"taken alon thel-ineB-ii of Fig.1.

Fi 41s a perspective view oftheato ol with the .tqol bit, a toolhitclanrp, and a shim removed to reveal certain ccnstrnctional detailsof the tool holder. a a. v

Fig. 5 is aperspective view showing the-tpol r ffle-3 a sn ey ew f a eemp qirng gt or 6 whe m an.

bit and the shim are shevv'nlinth dra ngs an a shim rem re t veal cer an nstr r ticnal et ns' the t .iioider" li e.- 9 i j a rners we v w def hm h 9W9 ma of Fig. Gland, v

Ta secticpal vievv, taken along the Fi .170 is n ali Fi FY "Whilewt'he'f t i ehtion is ,sus eptihle e; varigns e ru nse e e scribed indetail the refe tendeii t6 limit the 1, H closed, lontfit' is intendedto c and alternative all'qyjsnch as tl n gstenearbicle. QBY means'of thetoolih'olqer ll l'ftheft H ,lzis fi'rmly sup e t i e ion m 4 ad st bl ntiidinally to ,ccx'ii ins" f or tvear 0n the bit 2.

T e 0 1 rhpmer .u ch es; an elon ated [bar orls pn m ne, member 3 avin ashan IA, of

her I3.

"The recess 16 is adapted to receivel the ,tcol hit I-Z, together wimaplate or shim, 24f which in this was is" interppsedh tweenthe lower face1,8 of the 'rece's'sland vwe. m 1 bitjcrz. ,The 24 vmay be secured .tothe, supporting member, [3 bysome suitable means such as a flat headedmachine screw .26. "I heitbel vlcit I2 is prqvided with a suitableputting fedgge 128 ;Which in this case extends at an angle .t'o thelongitudinal vaxis of the snppbrting member [.131 'Ifhe 'tgiol bit l2,the ni gm vahd the t p rt n membe '3 a trev ew w h uit ble Mm i e ,.3 ;3I, and 32 whichareiormedto rovide clearance for the. cutting ed 128. thesur ace 4- :3 13 eine generally in alinement with QIIB another.

In this instance the recess 16 in the suppprting meinber I 3 has atvidth vvh-ic'his ls" full 6f the mem er 3;]:ahd "thi: br z bifil .a n'b l M ami' sw n th 91.

3 34. The tool bit I2 has a lower surface 36 and a lateral surface 38which are adapted respectively to seat against the shim 24 and the sidewall 22 of the recess I6.

A hold-down clamp or plate 46 is provided for clamping the tool bit I2against the shim 24' and the side face 22 of the recess I6. clamp 60 ispreferably positioned in a recess-e2 formed in the upper portion of theretaining wall 34, the recess being provided with a lower face A l whichis generally parallel to the lower face I8 of the recess It. On itsunderside, the holddown clamp 46 has a laterally inclined longitudinalclamping surface 46 which is adapted to engage with a longitudinaldovetail notch 53 in the adjacent upper edge of the tool bit !2, the

notch 48 being provided with a laterally inclined lower surface 56forming an acute angle with the side face 38 of the tool bit I2. clamp30 is secured to the supporting member I3 by means of a suitable machinescrew 52 which extends through an aperture 54 in the hold-down clamp'andis threaded into the retaining wall 34.

Provision is made for backing up the tool bit I2 to prevent it fromshifting longitudinally under a cutting load. For this purpose the barI3 is provided with back-up means 56 including a tool backing memberinthe' form of a wedge shaped plate 53. The member I3' has asubstantially smooth upper supporting surface 69 situated behind therecess I6, and the back-up plate 58 has a lower substantially smoothelongated wedge surface 62' adapted to seat against the surface 56. Thetool bit I2 has a rear abutment or thrust transmitting face 64, and theback-up plate 58 has a front face 66 adapted to-abut against the rearface 66. Theback-up plate 58 is provided with a substantially smoothelongated upper wedge surface 68 inclined downward away from the frontface 66 so that the back-up plate 58 tapers away from the tool bit I2.The back; up plate 58 is secured to the supporting member I3 by amachine screw which extends through alongitudinal slot I2 in the back-upplate 56 and is threaded into the member I3, the screw I0 being providedwith a head H for clampingly engaging the surface 68. As shown, thescrew 16 extends perpendicularly to the upper wedge surface 68 so thatthe head 'II of the screw will squarely engage the surface 68. Withrespect to the supportingsurface 60, the screw '10 makes an acute angle.

When the illustrative tool holder of Figs. 1-5 is to be used, the toolbit I2 is placed in the recess I6 on top of the shim 24 and under theholddown clamp 40. The clamping screw 52 is tightened down so that thehold-down clamp til holds the tool bit" I 2 against the shim 24 and theretaining wall 65, the tool bit I2 being held against the retaining'wall34 by virtue 'of the lateral inclination" of the lower-surface 50of the longitudinal notch 48in the tool bit I2. The wedge-shaped back-upplate 58 is moved forward until its front surface 66 abuts against therear surface 66 of the tool bit 12. The back-up plate 58 can be swiveledon thescrew lfi 'to provide-full bearing contact between the plate 58andthe tool bit I2;

even though the'plate 58 and the bit I2 may not be absolutely square.The clamping screw Ill-is then tightened down to hold the back-up memeber 58 against the upper surface 60 of the bar I3.

When a longitudinal cutting .load is applied to the tool bit I2, thetool backing means 56 prevents rearward shifting of the tool bit I2. Thetool backing member 58 is held fast against rearward shifting by wedgingaction between the The holddown The hold-down 4 head II of the clampingscrew 10 and the upper surface 60 of the supporting bar or member I3.Any tendency toward rearward shifting merely increases the intensity ofthe wedging forces between the clamping screw I0 and the back-up member58 so that the resistance to the rearward shifting. is correspondinglyincreased. The wedging action between the back-up member 58 and theadjusting screw I 0 provides a great frictional resistance to rotationof the clamping screw 10 and thereby prevents the screw 10 from becomingloosened accidentally.

After a period of use, it may become desirable to adjust thelongitudinal position of the tool bit I2. Such longitudinal adjustmentis occasioned by regririding of the bit [2 for example. When the toolbit I2 is to be adjusted, the clamping screws 52 and 10 are unscrewedsomewhat to loosen the hold-down clamp i0 and the back-up member 58. Thetool bit I2 is adjusted to the desired position and then the clampingscrew 52 is screwed down to tighten the hold-down clamp 40. The back-upmember 58 is moved forward until its front face 66 abuts against thetool bit I2. Tool bits having widely different lengths can beaccommodated because the slot 54 in the back-up member 58 provides aconsiderable range of longitudinal adjustment. The back-up member 58 isclamped in place by tightening the clamping screw I6. Because of thewedging action between the clamping screw 16 and the back-up member 58,the latter can be clamped in place in any position within the range oflongitudinal movement provided by the slot 54.

The improved tool holder is unusually inexpensive to manufacture. Theback-up affangement is particularly noteworthy in this respect.

The second illustrative embodiment of Figs.

6-10 is similar in most respects to the first illustrative embodiment ofFigs. 1-5, and most ofthe components of the second given the samereference characters as applied to the corresponding components of thefirst embodiment, with the addition of a prime suflix.

In Figs. 6-10 a tool holder II is shown, including a supporting bar ormember i3 having a shank l4 and an enlarged head 19 provided with a toolreceiving recess IS. The recess I6 has lower, rear, and side walls I8,26 and 22 respectively, and in this-instance the side wall 22 extends atan angle to the longitudinal axis.

of the bar I3. A shim 24 is secured to the lower surface I8 of therecess I6 by means of a machine screw 26, in order to position the toolat the desired elevation. The tool bit I2 has a suitable cutting edge28, and the tool bit I2, the shim 24, and'the bar I3 are provided withsuitable surfaces 30, 3i and 32 to provide clearance for the cuttingedge 28.

The supporting bar or member I3 has a lateral retaining portion 34bounded by the side surface 22 of the recess I6. In this instance a shimis seated against the side surface 22 of the recess I6 and is secured tothe bar I3 by suitable means such as a machine screw 62. The

tool bit I2 has a lower surface'36 adapted to engage with the shim 24,and a lateral surface 38 adapted to engage with the shim 80.

The tool bit I2 is clamped in place in the recess I6 by means ofhold-down clamp 40 positioned in a recess 42 formed in step-like mannerabove the recess I6 in the bar I3. The recess 42 has a lower surface 44which is generally parallel with the lower surface It of the recess I6."The'hold-down clamp llr has a concave embodiment have been rea ersarchdike lower surface 84 including a laterally inclined longitudinaledge portion 46 which isadapted to engage with a longitudinal dovetailnotch!!!" in the tool bit [2. The notch 48' has a laterally inclinedlower surface 50" to retain the tool bit l2 in the recess I6. A clampingscrew 52" is provided for securing the hold-down clamp 40'' to the barI3. The clamping screw 52" extends through an aperture 54- in theholddown clamp 40' and is threaded into the lateralretaining portion 34'of the bar l3".

The illustrative tool holder of Figs. G- lO'includes tool backing means=56 comprising a wedge-shaped back-up member 58'. instance the back-upmember 58' is seated in a recess86 formed in step-like fashion to"therear of the recess l6 and having a .lower surface 60' to support theback-up member 58. The backup member 58 has a lower surface '62engageable with the lower surface 65' of the recess 86. The tool bit I2and the back-up member 58' have interengageable end surfaces 64 and 66'respectively. The back-up member 58' has a longitudinally inclined uppersurface 68 so that the back-up member 58' tapers away from theendsu'r'face '66. A clamping screw 10' extends through a longitudinalslot 12 in the back-up member 58 and is threaded into the bar l3, thescrew being provided with a head H for clampingly engaging the upperSurface 68' of the backup member 58'.

The operation of the embodiment in Figs. 6-10 is similar to that of theembodiment of Figs. 1-5. The wedge-shaped back-up member 58 preventslongitudinal rearward shifting of the tool bit l2, even when a heavycutting load is applied to the tool bit l2. The wedging action of theback-up member 58' between the head 1 I of the clamping screw 10' andthe supporting bar I3 prevents retrograde movement of the back-up member58' and accidental loosening of the clamping screw 10'. The wedgingmember 58' may be adjusted to any position within the range oflongitudinal movement provided for by the slot 12.

Infinitely fine adjustment of the back-up wedge member is possiblebecause the wedging surfaces are smooth and unbroken. For carbide toolbits, this extremely fine adjustment is highly advantageous, because thebrittleness of carbide bits requires that they be fully supported by thebit holder. Consequently, the bits should be set flush with the end ofthe holder, without any overhang. Moreover, the infinitely fineadjustability provided by this invention minimizes the amount ofgrinding required to sharpen the carbide bits, which are difiicult togrind.

I claim as my invention:

1. In a cutting tool, the combination comprising a supporting member, atool bit slidably mounted on said member for adjustment in apredetermined direction, means for releasably holding said bit on saidmember, said means including a backing member slidably mounted on saidsupporting member for adjustment substantially in said predetermineddirection for engaging one end of said tool bit, said backing memberhaving a pair of elongated substantially smooth relatively inclinedwedge surfaces defining wedge means tapering away from said tool bit insaid predetermined direction, and clamping means engaging one of saidwedge surfaces for clamping the other of said wedge surfaces againstsaid supporting member, said backing member thereby being wedged betweensaid clamping means and said supporting member so In this asteeffectively back :up said bi-t against. moves-j ment -in -saidpredetermined direction.

Iri a holder for a tool bit having, a for wardly disposed cutting: edgeand a rearwardly disposed thrust transmitting surface, thecombinationcomprising a supporting member having supporting means forslidably receiving the bitfor forward andirearward adjustment to advanceandretract the cutting edge, a backing member slidablymounted: on saidsupporting member rearwardly ef-saidsupportingmeans for forward andrearward: adjustment "to engage the thrust transmitting. surface andback up the 'bit, said back-mg member having a pair of elongatedsubstantially smooth wedgessurfacesdefining a wedge porti'ontazperingrearwardly away from said .supporting means, one :of said wedgesurfaces being slidably engaged with said supporting member,

and a-clampingmember engaging the other of ,said-wedge surfaces forclamping said backing member against said supporting member, said" back-ingimember thereby being wedged between said zclamping memberand saidsupporting memberso a's to effectively back up 'said backing. memeholding said bit on said supporting member, said means including a wedgebacking member having a front end portion for engaging said thrusttransmitting surface on said bit, said wedge member having a pair ofelongated substantially smooth, relatively inclined wedge surfacesconverging gradually toward each other in adirection rearwardly of saidbit, said wedge surfaces being generally parallel to said undersurfaceof said bit, said supporting member having a smooth surface disposedrearwardly of said bit for slidably supporting one of said wedgesurfaces, and a clamping member for engaging the other 01' said wedgesurfaces and clamping said wedge member against said smooth surface onsaid supporting member, said wedge member thereby being wedged betweensaid clamping member and said smooth surface so that said wedge memberwill be immovable rearwardly under thrust-loading imposed by said bitduring cutting operations.

4. In a cutting tool, the combination comprising a. cutter bit having anundersurface, a cutting edge at its front end, and a thrust transmittingsurface at its rear end extending transversely to said undersurface; asupporting member having a supporting surface for slidably engaging saidundersurface, said bit being adjustable forwardly and rearwardly alongsaid supporting surface; means for holding said bit immovably on saidsupporting member, said means including a wedge backing member having afront end portion for engaging said thrust transmitting surface and apair of elongated substantially smooth relatively inclined wedgesurfaces converging gradually toward each other in a directionrearwardly of said front end portion; said supporting member having asubstantially smooth surface disposed rearwardly of said bit supportingsurface and generally parallel thereto for slidably supporting one ofsaid wedge surfaces; said wedge member having a slot extendingtherethrough transversely to said wedge surfaces, said slot beingelongated in a front-to-rear direction able rearwardly under the thrustimposed by said bit during cutting operations.

5. In a holder for a tool bit having a cutting edge at one end and anabutment surface at its opposite end, the combination comprising asupporting member having a surface for supporting said bit for forwardand rearward adjustment therealong, means for releasably holding saidbit iimnovably on said supporting member, said means including a wedgebacking member having a front end portion for engaging said abutmentsurface on the bit, said wedge member having a pair of elongatedsubstantially smooth relatively inclined wedge surfaces converginggradually toward each other in a direction rearwardly of said front endportion, said supporting member having a substantially smooth surfacedisposed rearwardly of said supporting surface and generally parallelthereto for slidably supporting one of said wedge surfaces, and aclamping member for engaging the other of said wedge surfaces andclamping said wedge members against said smooth surface on saidsupporting member, said wedge member thereby being wedged between saidclamping member and said smooth surface so that said wedge member willbe immovable rearwardly under the thrust imposed by said bit duringcutting operations.

References Cited in the file Of this patent UNITED STATES PATENTS

